Metabiosis
by sleepling
Summary: A newly-acquired symbiotic consciousness threatens Donna's safety, and may have consequences that affect the Ponds. Eleven, Donna, Amy, Rory, River
1. Chapter 1

A/N: Thanks to grumpyjenn for the beta!

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><p><strong>Metabiosis <strong>

Clad in his shirtsleeves, the Doctor sat in the repair swing under the base of the time rotor. The Tardis was being sulky and he was waiting for a systems diagnostic scan to finish. It would take a practically intolerable five minutes to complete; he had already rebuilt the Orthogonal Navigation Array, polished all the thermo-coupling connector points, and now he was bored.

He turned himself in anticlockwise circles until the chains supporting the swing were completely twisted. "This is Tardis One, we are go for launch. Ignition in 3, 2, 1..." He made a rumbling noise as the chains unwound, spinning him in place like a top. "Escape velocity achieved," he giggled dizzily to himself.

There was a loud snapping noise from above.

He shrugged and began twisting the swing for his seventh go round. Probably one of his companions breaking something. They were always doing that. He released his feet and watched the tangle of overhead cabling whirl past him.

Except he wasn't traveling with anyone presently. Memory caught up with his swimming head. He had dropped off his last companion, a Hath chap called J'gorr, at least 25 years ago.

The Doctor unsteadily made his way up the stairs, only slightly bouncing off the railings in a dignified lurch. A familiar but improbable figure was leaning against the Tardis doors, watching him.

"Ah, Noble, there you are." Nodding, he braced himself on the console with his eyes closed. "Be with you in just a mo. A bit disorientated. Either I've managed to spin myself into the past, sort of Superman-flying-around-the-Earth, or something spectacularly _very bad_ is about to happen. If I had any money, I know where I'd place my bets."

"Nice to see you too, Spaceman. I like the new Tardis desktop. The bow tie? Ehh, as long as you're happy."

"Bow ties are cool, but not effective distraction topics. Here's a better one- what are you?" Eyes still tightly squinched shut against the nausea, the Doctor put on his tweed jacket and straightened the aforementioned bow tie. He had a guest on his ship, even if it was something nasty impersonating his long-lost best friend.

"Doctor, it's Donna. Do you remember me? We... we used to travel together, a long time ago."

"I know who you're _supposed_ to be. That's probably not a basic clone-job as I don't smell hydrocarbon polymers. And the hair, it looks too good. Genetically modifying the chromosomes for that shade of ginger is tricky. Not that I tried it on myself four times. Ok, so more advanced. You're wearing a Time Agency-issue vortex manipulator and they don't work with Gangers. Tesellecta wouldn't need it. Got to be coming off as biologically human or the Tardis would have automatically blocked materialization. Or there's the more metaphysical-y, psychic possibilities! But you're awfully benign for a manifestation of my subconscious..."

"Blimey, you can still gabble on! Guess some things never change. Hey, do you always _have_ to be a weedy bloke with impossible hair or is that on purpose?"

"Rude! Maybe I spoke too soon." The Doctor stuck out his tongue in the direction of the voice.

Clicking boot heels marked passage up the steps to the platform, coming to rest a meter to his right. This close, he could detect the lingering ozone from unshielded rift travel. The Doctor blindly fished out his sonic screwdriver and scanned the spot.

"Stop bleepin' me," said the voice affectionately.

Feeling less vertiginous now, he risked a squinting glance at the readout.

"It's you. Actually, really _you_. Here. Oh, Donna," the Doctor breathed. Stepping into her personal space, he alternately peered into her face and at the sonic. "How?"

"Well, it wasn't from drinking dodgy coffee this time," she joked.

Making a choked noise, the Doctor pulled her into a hug that nearly lifted her off the ground. "I've missed you so much. Never thought I'd get to see you again. Brave, brilliant, beautiful Donna!"

He could hear her automatically draw in a sharp breath, undoubtedly to give voice to a self-disparaging comment. But instead she sighed after a moment and gently thumped his back. "Daft alien."

"I wish we had time for a proper reunion. You could tell me about your life and we'd have cakes and jam and fish custard- kindly withhold your judgment until you've tried it- and we would play table tennis with Neil DeGrasse Tyson and we'd laugh and maybe I'd cry... But you can't be here, Donna. We've got to get you back to Chiswick immediately. Every second that you're remembering your life on the Tardis is a moment that could set fire to your mind."

Donna pulled away from the hug. "About that. I'll be fine for an hour or two. The metacrisis energy is being managed for now and it bought me some time. There are some things I have to tell you."

"Managed? It's not something you can hold off like a... trip to the _loo_ or something." The Doctor crossed his arms over his chest and regarded her seriously. "This is the consciousness of a Time Lord, fueled by the regeneration energy you absorbed. It will sweep through your mind and burn everything in its path. Think Pompeii. I have every faith in you, Donna, but this is beyond your ability to control."

"It's not _me_ that's holding it back. God, this is going to sound bonkers... There's a third entity in my mind now. A symbiotic consciousness that can neutralise the metacrisis for a time."

"But that's wonderful, maybe I can work out a way to make it permanent! What species is the consciousness? There are some perfectly lovely symbiotic races out there that would be happy to make your red noggin their new nest. Well, some are less 'lovely' and more 'tentacley,' but I don't imagine you're squeamish. My Noble never met a calamari appetizer she didn't like." He clapped his hands and grinned at her.

Donna sighed. This was the part he wasn't going to like. "Time Lord."

The Doctor looked at her expectantly as if she had called his name.

"No, you great... I'm saying _it's_ Time Lord. As in, two chrono-temporal presences havin' a battle royale in my brain, alright?"

The Doctor's face became suspiciously blank. "Sorry, _what_?"

* * *

><p>TBC<p> 


	2. Chapter 2

**One year ago:**

Donna was at a loose end. Her marriage to Shaun Temple had ended, badly, almost right after it started.

One day soon after they got back from their honeymoon, she had looked into husband's kind and open face and found that it wasn't enough. She thought she wanted a married life, but it didn't make her happy. Donna couldn't get over the feeling that she was just making do. It wasn't fair to stay with Shaun just because it felt nice to have someone look at her like she was the most important woman in the universe. The guilt over hurting her new husband was crushing, but it was better to end it than to live a lie. He was a good man and he deserved a wife that could offer her whole heart. It just wasn't going to be Donna Noble.

He had been confused when she asked for a divorce. They never fought. Neither had been unfaithful. Money wasn't a worry. It should be anyone's dream life. Hadn't this been her goal since she was a little girl? Donna wondered if she was broken. She felt... wrong. Something had changed within her soul and it was like she didn't even know herself anymore. Despite her self-recrimination, Donna was heartbroken. She grieved for what she had lost, without knowing what it was.

People told her to take solace in her half of the lottery fortune, but the temp-turned-millionaire had never found comfort in money. She missed a feeling of friendship and _belonging_. What she needed was a mate, Donna decided. She sought this out in her usual social circles, but it wasn't working. It seemed like all she encountered were blokes hitting on her, gossips judging her failed relationship, or acquaintances with expectations that just didn't seem to fit Donna anymore.

She couldn't bear to burden Wilf, because that sweet man would be hurt on her behalf. Donna didn't bother to approach her mother. Sylvia had made an effort to be more kind, but the woman still had the emotional depth of a multispan's Convexity Reserve, whatever that was.

Donna thought about just leaving Chiswick. Maybe travel and try to find herself, like some kid on a gap year. No, she was an adult and she would _make_ her life work through sheer willpower. And shouting. She just wished that she didn't have to do it alone.

The headaches had persisted after the mysterious accident that wiped years from Donna's memory. They were more likely to flare up when Donna watched the news or read current events, so she had taken to escaping reality in novels.

Donna stopped by a bookshop on Wednesday in December. She had finished reading all of Agatha Christie's novels and wanted to find a new series. As she left with her purchases, someone pressed a flyer into her hands. When Donna arrived at home she was still clutching it tightly. She unfolded it and read:

_Looking for a new mate? - Meet fellow bibliophiles - Online book clubs starting now_

She snorted. Online book club? Might as well replace her wardrobe with polyester and get a dozen cats. But... she was looking for something new. And the people she would meet would be different than the type that invariably talked to her in the pub. What's the worst that could happen?

Donna went to the webpage and created an account. There were thousands of groups listed, so she selected the option to match her to the most compatible group.

The questionnaire was remarkably thorough. Everything from marital status, favorite genre, the last book that made her cry, right or left handed, opinion on the validity of the moon landing, number of teeth (mouth only), favorite subatomic particle, which flightless bird best describes her personality, to preferred tea blend. It went on and on for pages.

At its conclusion, Donna was shown her results: There was only one matching group, which had a timestamp listing its creation five minutes earlier. At least she wouldn't have to worry about fitting in with an existing one.

This group only had a single member so far, who was apparently someone that the system thought would have compatible tastes. Not bloody likely. Most of the questions were ridiculous, so Donna had put down made-up answers for most of them, like "Felspoon" for the planet she'd most like to visit.

Donna shrugged and clicked the link, which was labeled _Wanderers in the Fourth Dimension__._

* * *

><p>TBC<em><br>_


	3. Chapter 3

**Six months ago:**

"_Think about it at least. It might do you some good to get out. Bit of cake, bit of alcohol- you know, fun!"_ Donna typed, fingers flying over the keyboard._  
><em>

"_I'm sorry, I know this means a lot to you. It is just not possible."_

Donna grumbled in frustration as she read the reply. She fixed her laptop with a beady glare that would have made it yelp if it were able. People usually caved in the face of the redhead's indomitable will (or sharp tongue, if she were honest with herself) but her friend was proving to be just as stubborn.

Over the past months, Donna and her book club buddy "Epsilon0" had become quite close. The username was apparently a maths joke, but Donna charitably forgave this of the poor idiot. No one else had joined their group, so they had decided to make a go of it with just the two of them. They took it in turns to pick the book that they'd read and discuss.

After Donna had adored the first few suggestions she received, she found that Epsilon's tastes were eclectic but still spoke to her. They were equally voracious readers, which was remarkable because Donna's Super Temp ability to speed-read meant that she went through several books a day. Together their little group tore through everything from Greek plays, tomes of fairytales, scientific treatises, graphic novels, to biographies of people Donna had never heard of but were never the less fascinating. Lost in a world of words, she was able to temporarily forget her heartache.

"_Please? Please! Please please please please?"_

"_Apparently semantic satiation negates guilt trips, so no." _

"_Cheeky!"_

"_You love it."_

As they got to know each other in a shared journey through prose, Donna had felt comfortable mentioning her personal life. Epsilon had lost a spouse as well. Neither got into the specifics of their personal pain, but she felt united in the loss of something neither could properly verbalise. Donna told her friend about frequent migraines that she suffered, her divorce, and the unknown emptiness in her life. She talked about mundane things like stargazing with her grandfather as they huddled over mugs of hot cocoa.

Donna initially felt like she was boring or depressing, but she soon realised that the other person was sincerely interested in her stories, almost living vicariously through her. Her friend didn't seem to have a job or a social life, no ties to the world. Donna wondered if Epsilon was a shut-in of some sort. She felt a rush of empathy for someone that obviously had no friends or family in their dark times.

Over all else, she knew that her friend needed human contact, to not feel alone. Donna tried to be the rock of reality in the stream of fantasy through which they swam.

Enter Donna's birthday party. The one that Donna had been dreading, and she hadn't even had time to prepare. She shouldn't even be 40 yet. It wasn't fair. Years should only count against your age if you can _remember_ them. Nerys was planning a birthday do, full of all the people Donna had been avoiding.

"_Oh, come on, then. I could really use an ally there. NERYS and my MOTHER! Need I say more?"_

"_I can't explain it, but there are some very good reasons why I can't."_

Yesterday she had impulsively invited her book club buddy to her party.

Donna was convinced that Epsilon was from somewhere near London. Some of the books her friend suggested were self-published in small numbers, like the slim volume of poetry written by a local author, Sally Sparrow. It would be difficult for someone outside the city to buy a copy. Though this wasn't solid proof, since Eps had at times listed rare works that Donna couldn't find. A clerk at the bookshop had once told her that a particular book, _Harry Potter and the Return to Hogwarts_, hadn't been completed yet. Clearly Donna needed to find a shop with a more informed staff.

"_You're right, of course you're right. I mean, you don't even know my name. I could be anybody. For all you know, I'm an alien,"_ Donna joked.

"_Well, everyone's an alien somewhere. Just a matter of scale."_

"_I just think that you need something real in your life. If you're not up for a party, we could at least meet for coffee. Somewhere safe and public. You wouldn't have to worry that I'd hurt you."_

"_No, look... Not having all of the pieces to the puzzle is normal for me. I know all that I need to: your compassion, your heart. This isn't an issue of trust. Please believe that nothing would make me happier than to see you, but I'm not physically able and I can't explain it in any way that would make sense."_

"_I'm sorry, I didn't mean to push. You don't have to tell me your reasons. Just tell me if there's anything I can do to help, ok?"_

"_Thank you. Go, have good time! You deserve a bit of happiness. Just get pissed and snog a few handsome strangers for me!"_

"_Will do, sunshine. It wouldn't be a proper Donna Noble birthday without a few questionable choices all around! My friend Suzie woke up on a bus to Swindon last time. With no wallet, mind you. Guess who had to go pick her up from the depot?"_

There was a pause, which expanded into a full-blown awkward silence. Epsilon was nearly as fast a typist as Donna herself, and had just as much to say. Usually they communicated at lightning speeds.

"_Your name is Donna Noble?"_

"_Yeah, but you don't have to tell me what you're called just because I did."_

"_From Earth? London in the 21st century?"_

"_No, New London on Mars in the year Pineapple. Of course Earth you barmcake! Though some days I don't half wish... Anyway, nothing as interesting as that- I'm just boring old Donna from Chiswick."_

Another long silence.

"_I keep crossing boundaries and making you uncomfortable today. Forgive me? Must be going daft in my advanced age. Let's talk about something else, yeah_?" suggested Donna, trying to salvage the conversation. This was not going as planned.

After a few minutes, Donna went to make herself a nice cuppa. When she returned there was a new message waiting.

"_It appears that the universe is telling me I'm not done saving you."_

"_What are you on about? Can you stop being flippin' mysterious and make sense for five consecutive minutes today!"_

"_Would that I could. I'm not sure how this happened, but there is something that isn't finished with either of us."_

"_And what, exactly, is that supposed to mean?"_

"_Spoilers, sweetie."_

* * *

><p>TBC<p> 


	4. Chapter 4

"_Will do, sunshine. It wouldn't be a proper Donna Noble birthday without a few questionable choices all around! My friend Suzie woke up on a bus to Swindon last time. With no wallet, mind you. Guess who had to go pick her up from the depot?"_

Three millennia in the future and 2714 light years away, River Song's communicator dropped from her nerveless fingers.

A double-heartbeat later and she had retrieved the device from her lap, and tapped it absently against her chin in thought.

Donna Noble? No. Not a chance. What were the odds that of all of the people across space and time that River could befriend from inside the hard drive of a supercomputer in a doomed Library, it would be the Doctor's best mate? She quickly totted up the numbers in her head- next to impossible. So of course it should have been obvious that this would happen.

River thought about how she arrived at this point. The Doctor had fixed the hard drive so that no one was forced to live in the little girl's dream; the uploaded minds retained their independence, of sorts. They could choose to go anywhere, do anything, in the virtual world. If someone had written about it, they could experience it. River, ever the academic, had been enthusiastic at first about exploring the collected wisdom of a hundred planets.

Years went by, possibly centuries. It was hard estimate time when a bespoke universe bent itself to your will. The distinction between fantasy and reality became distressingly vague. The scraps of your own memories could seem pale and remote compared to the stories from a million million books brought to life.

The team from the expedition grew apart and eventually scattered. Other Dave was currently living as King Arthur, and Anita had disappeared with Proper Dave into a domestic white-picket dreamworld on Keppler 22b. Miss Evangelista had remained lucid for longer than the others. But she too had changed, eventually. The former personal assistant had abandoned the projection of her body to become a being of pure thought, only to be sometimes glimpsed flitting through a Philosophy sector like a moonbeam.

Seeing the building disconnect in her human friends, River fought to remind herself of things that were real. Amy's closely guarded recipe for the perfect margarita. Her first solo dig, three months on the desert moon of Argos VII. Running beside the Doctor. The way her dad scoffed when he received a compliment. The faces of the Farr Harbor survivors. The reassuring weight of her alpha-meson blaster against her leg.

She would not lose her hold on reality. Would not be stuck here for an eternity while her mind unraveled. She focused on escape. There is _always_ a way out.

A bored/frustrated genius can cause a lot of mischief when given free reign within a supercomputer, and River Song had given it a solid go. Kicked all the tyres and rattled all the doorknobs. Exploring the boundaries of the security protocols one day, she found a gap- a tiny but exploitable logic flaw in the communications subroutine.

She sent a query through the gap and was surprised to get an automated response. It was an old fashioned Earth website, some kind of book club, but it wasn't an archive. River tried to expand the connection so that she could get a message to... well, anyone that could potentially help her, but it was deadlocked. Even if it lead to nothing, at least it was a window to the real world, River had rationalised as she created her own group.

And on the other end of that connection had been Donna Noble. Possibly. A fluttery sensation that River hadn't felt for a while was making her hearts beat faster- hope.

"_Your name is Donna Noble?" _River typed. "_From Earth? London in the 21st century?"_

"_No, New London on Mars in the year Pineapple. Of course Earth you barmcake! Though some days I don't half wish... Anyway, nothing as interesting as that- I'm just boring old Donna from Chiswick." _

Self-deprecating, slightly insulting, and deeply empathetic. Oh, that definitely sounded like the spirited redhead River met on the day she died.

River remembered what the Doctor had told her about the events on the Crucible, when the Earth had been plucked from its orbit and used to power the Reality Bomb. Dalek Caan had manipulated the timestreams, bending causality and destiny to his will in order to bring about his prophecy. The Time Lord part of her shuddered involuntarily. It had bound her friend Donna to the Doctor in ways that River couldn't hope to guess. No matter how deftly done, these things almost always had far reaching ripples. Why had they just assumed that it ended with the creation of the half-human metacrisis Doctor?

"Something trying to tell me somebody," River quoted to herself. An outside force was still directing Donna Noble's timeline. Possibly her own as well. It had brought them together, surely for some purpose.

She couldn't sense timelines here in the Library's hard drive, but she didn't recall _feeling_ anything when she had met Donna in person. River was sensitised to changes in her personal history. It was an odd sliding sensation when that happened, like her mind lost traction for a split second until the new memories solidified. And she hadn't detected anything anomalous that day. They had been running from carnivorous shadows at the time, so perhaps she was distracted. Up until the very end River had been confident that they'd all walk away, the Doctor and his friends, like they always did. But she wasn't _that_ Doctor's friend, and she would never walk in the real world again.

River had died to save the Doctor, Donna, and 4022 others, but she didn't feel compelled to do it. No one, even an insane Dalek, could force the hand of Dr. Song. Not anymore. Her sacrifice had been made in the same way she made all of her major decisions: impulsively and out of love. River might have her mother's temper, but she had the same loyal heart as her father.

River tilted her curly head back over the edge of her chair. How could she not have seen this possibility? The Doctor hadn't felt the manipulations on his own timeline, though that wasn't saying much. How that impossible man could see everything and nothing, she would never know.

If their timelines were entwined, River still had a part to play in Donna's life. An idea was brewing.

River laughed with genuine merriment. Oh, this was going to be fun.

* * *

><p>TBC<p> 


	5. Chapter 5

**One week ago:**

Donna absently touched her pocket again, reassured by the feel of the folded paper within. River's instructions. She had reread them a dozen times, but still printed it out in case her memory failed.

It was two hours from Chiswick to Gloucester, where she had stopped for petrol, then a half hour north to a village so quaint it belonged in a storybook. Now she sat in her idling car, wondering if she had made the trip for naught. One last piece was needed. If she quit now, the last six months of planning would be wasted. Not to mention the outrageous sums of money she had spent; plain-wrapped parcels of unknown provenance were still appearing on her doorstep. She squared her shoulders. Since when did Donna Noble back down from anything?

Right on time, two people emerged from the house across the street. She watched them as they chatted while closing the bright blue door behind them. After they drove off in a sports car, Donna exited her own. She retrieved a shovel and work gloves from the boot.

Donna walked to the back of the attached houses and located the appropriate garden. Thankfully the gate had a simple latch instead of a lock, so she was able to let herself in without causing a racket. Several former lovers could attest that the fiery redhead wasn't above kicking in a door or two.

After surveying the layout for a moment, she pulled out the map to double check her position. It was a lovely garden, predominantly purple and silvery green, and Donna didn't wish to disturb it any further than necessary. Overflowing beds of sage, foxglove, lamb's ear, and lavender grew in the shade of two willow trees.

"Fifteen paces from the edge of the patio. Left turn. Six paces." Donna rolled her eyes. Trust River to write a map like a pirate. She compared the listed coordinates against the GPS on her mobile. "Result!"

Wincing a bit in remorse as she pulled up the first shovelful of dirt and purple blossoms, Donna began to dig.

The hole was half a metre deep before she heard the _thunk_ of the shovel blade hitting a solid surface. She scraped away the dirt to uncover the top of a small metal box. Donna stretched her aching back and tossed the tool over onto the grass.

"What _exactly_ are you doing?" asked an amused Scottish voice from behind her. Donna froze in place. "RORRRAYYY! Come see the state of the backyard."

"That badger hasn't gotten in again, has he?" She heard someone else walk out onto the patio. "Oh! My violets."

Donna put her hands up in a gesture that she hoped meant I-only-assault-flowers-not-people and turned around. She saw that the voices belonged to the couple she had seen leave the house earlier, a beautiful fellow ginger and a tall man with sandy hair and soulful eyes. "I'm so sorry! I can explain! Sort of."

The woman laughed. "First, out of that hole and into the kitchen. Second, we had better clean you up and get some tea in you. Third, you will 'explain' all this."

"Amy," warned the man.

"Well shoveling is hard work, yeah?"

Donna nodded gratefully and stepped out of the mess she had made of Rory's garden.

* * *

><p>TBC<p> 


	6. Chapter 6

"Earl Grey ok?"

"Yes, thank you."

"Jammie Dodger?"

"Please."

"Now, what is so fascinating at the bottom of our garden?"

Donna stared into the amber depths of her cup. "I don't know. I mean, I know there is a box buried under your violets, but I don't know what's in it. The person who hid it asked me to get it back. I am really sorry about the hole, and I feel terrible about destroying your lovely flowers. I was going to leave this for you. For the damages. " She produced a white envelope from her back pocket and offered it to Amy.

"Pond. It says 'Pond' on it. How did you know our last name?"

"Williams, actually," muttered Rory automatically.

"Got it from online?" Donna offered weakly.

Amy opened the envelope. "There's over a thousand pounds in here." She fanned the stack of notes at her husband.

"Hopefully you can get a landscaper in to put it back to rights. Add a water feature if you like. If that's not enough for the inconvenience, just let me know what it would take."

Amy looked speculatively at the money. "You're rich. So why didn't you just knock on the door and ask to buy the box?"

"And miss this deeply shaming experience? I didn't know what your answer would be. Better to ask forgiveness than permission, I guess. Couldn't risk you saying no or getting curious about it. The box is important to me, personally. Whatever it is," said Donna to her biscuit before taking a bite.

Rory had been watching their guest carefully from the start. The expression Donna wore now... he knew it well. He had worn that same look on his face for two years, though less if you didn't count when he was dead. Like awe, terror, hope, and misery, all bound together into one overwhelming emotion by adrenaline. He beckoned his wife closer for a private word.

"Amy, that flowerbed has been undisturbed the whole time we've lived here," he whispered.

"The previous owner maybe?"

"Or someone could have put it there a hundred years ago yesterday." Rory raised his eyebrows meaningfully.

"That would make sense." Amy took advantage of his proximity to place a quick smooch on his cheek. As expected, the public display of affection made Rory sit back with a start and flush prettily. She smirked and he cleared his throat disapprovingly at her.

"So, um..." Rory belatedly realised they didn't exchange names with the muddied stranger. "Did the Doctor send you?"

"Yes, it was the doctor! Please feel free to blame the doctor." Donna sighed in relief. They must know Doctor River Song. Her head was starting to twinge a bit; the sooner they finished the most awkward teatime ever, the better.

"And he didn't have any instructions on say, handling radioactive material or brain slugs from Ganymede?"

"Not as such... Wait, _he_? We've only talked online, but I thought the doctor was a woman." Frowning, Donna tried to remember if Dr. Song had specifically referred to a gender. Had she just assumed? River was sort of a feminine name, for a noun. And the spouse that River lost was a husband. Oh dear. Donna was ashamed to have made such a heteronormative assumption about her friend, and vowed to be more open-minded in the future.

Rory hooted with laughter, until a withering look from Amy sobered him. "Sorry, but you have _got_ to stay for supper. I need to hear all of your theories regarding the Doctor."

"These are the directions he emailed to me." Donna smoothed the folded papers open on the table.

"This symbol is Gallifreyan," murmured Amy. She pointed to the legend next to a small, sketched diagram of a device. "Wonder why he didn't come collect it himself."

"He said he wouldn't involve us in this sort of thing anymore," Rory reminded his wife softly. "The Doctor is protecting you. Please let him do that for our family."

Amy nodded, protectively laying a hand on the gentle bulge of her lower abdomen.

"Oi, I am not a delivery service! If he could do it, the doctor would be out here digging his own ruddy trenches, I'll have you know! He's stuck in a library and he asked me to help. Then he's going to restore my memory with that... thingie. So if it's all the same to you, I'll have my box and be on my way." The headache steadily growing behind Donna's eyes was making her tetchy.

"Well, let's go open it then," exclaimed Amy.

All three filed out into the garden. Rory carefully worked the metal box out of the soil. Upon seeing the keypad on the front, he offered it to the non-wife ginger. Donna entered a code from her printout, and the lock released with a pneumatic hiss. She eased back the lid to reveal its contents. A battered leather cuff sat inside.

"A really big watchband?"

The Ponds exchanged a look.

"That's River's vortex manipulator!"

Pain flared behind Donna's eyes as a golden glow slid over her vision. It felt like someone was treading on her brain with hobnail boots. She didn't even realise she was falling until Rory caught her arm to steady her.

" 'M fine."

"You are not. Nothing about this whole afternoon has been 'fine.' I am a nurse, and you are going to let me check you before you faint and ruin another flowerbed. I'm really fond of that hydrangea behind you."

"Better listen to him, he's gone all Roman. Love it when he does that," Amy leered at her husband.

The yellow glow in Donna's eyes intensified. "I'm sorry for everything that has happened. And for everything that's going to happen."

Moving with unusual grace, Donna whirled away from Rory, pulling her arm from his grasp. She snagged the wrist strap and was halfway across the garden before the Ponds could react. Donna turned back to them with a sad smile. "No time for goodbyes," she said and then vanished in a flash of electric blue and sparkly yellow.

Donna found herself back in her own home. Her head sang with exquisite pain. The last thing she remembered was opening the box. She was wearing a clunky wristwatch, so it appeared that her mission was successful. Nice couple, the Ponds. She placed the leather band with the rest of her materials and went in search of some paracetamol.

* * *

><p>TBC<p> 


	7. Chapter 7

**Yesterday:**

An exasperated _tut_ echoed off the basement's concrete walls.

Donna crossed her arms and stared challengingly into the lens of the tripod-mounted video camera connected to her laptop. She had hooked it up so that River could observe the design being assembled, which had been helpful when they had to improvise. The camera was focused on a wooden workbench cluttered with blueprints and cannibalised machinery, but Donna knew her friend could see her on the periphery.

"The last pieces aren't fitting together. Don't think they're compatible." The undertone of _are you sure you know what you're doing mate_ was evident in Donna's voice. She watched the computer's screen to await the response.

"_There should be a converter. Looks like a spider with a crystalline growth on its back," _read the message that popped up on the monitor.

The redhead collected a number of likely bits and bobs and held them up to the camera.

"_The seven-pronged one. Feed the legs into the ports in this order: grey, blue, fuchsia, splerranje, lime green, emerald green, then yellow."_

"Splerranje?" Donna inquired as she painted the exposed metal ends of the component with flux.

She picked out a pair of safety goggles that looked fetching with the parts of her outfit not covered by a knee-length leather welding apron. When they started this project, Donna had been surprised to find that she picked up the necessary mechanical skills as easily as she learned the Dewey Decimal System. Apparently 'Super Temp' was more like Super Anything Donna Puts Her Mind To.

"_Is that not a colour yet?"_

Wires sorted into their appropriate ports, she took the soldering iron from its stand and touched it to the first connection to heat it. "Let me guess- Did someone invent a new colour just to have a convenient rhyme for orange?"

"_Just a bit. I wouldn't fancy painting my bedroom splerranje, but it is nicer than bilver or hurple."_

Donna laughed. "Is everyone mad in the future?" She fed solder onto the heated junction, the silvery metal melting on contact. Donna blew a puff of air over the surface to dispel steam from the boiling flux and moved on to the next port.

"_I can only speak for the people I know, so that would be an unqualified yes. Can you send me the readings from the oscilloscope to your left? If everything is in range, we're done."_

Donna pottered about the workroom, tidying up while River did whatever she was doing on her side. Now that they were finalizing the project that had taken six months to complete, she was having doubts. It wasn't just a theory anymore; the actual machine was sitting right there, waiting to be used. She rubbed her temples to reduce the building headache.

"I know you can't tell me much, but I... The thing we just built. All this weird technology. I don't understand exactly what this does, but I know dangerous when I see it." Donna flashed a wry smile at the camera.

"_It is. Extremely, stupidly so."_

"We're both risking our lives."

"_Yes."_

"So why are you doing this for me?" asked Donna quietly. She seemed to compensate for the vulnerability by placing her hands on her hips.

"_You already know that I'm trapped, but it's more than that. I've been pulled out of space and time- Locked up more effectively by the guilt of my husband than my enemies ever could. This is my best chance for escape, freedom. In doing so, I can help you with your missing memories," _read River's response.

The screen flickered for a second, then continued, _"I cannot do it without you, but don't let that influence your decision. It's fine if you want to stop here. Won't be disappointed, because you're amazing. Won't ask you to do any more than you've already done, because this is too big. You have to choose this path for yourself."_

The redhead turned away from the camera so that River couldn't see her face. "Everything would change. Will I even be the same person when my memory is back? But I feel like this is important. Something I need to do. There's a life I was meant to lead, and _this_," she gestured emphatically at her surroundings, "Is. Not. It."

"_So then, Donna Noble, do you want to know who you are?"_

She rolled the completed device around in her hands for a moment, a crown of wire and metal, then placed it on her head. When Donna spoke, it was with complete confidence. "I do. I'm ready."

"_Push the button."_

"Oh bloody 'ell- Nothing ventured, nothing gained." Donna took a deep breath and jabbed the red button just above her right ear.

Little filaments of honey-colored energy began to drift through the still air. She waved her hand to disperse it like smoke, and noticed with shock that it was coming from her. Her pale skin was emitting soft waves of the golden light. Kind of pretty.

A bolt of pain stabbed through Donna's head. She staggered back against the workbench. Another spasm of white-hot pain cut through her body and left her gasping.

"Is this normal? Cos this doesn't half hurt," Donna managed to say between gritted teeth. Every nerve ending blazed with agony. "River! Is this what it's supposed to-"

She turned to the monitor for reassurance from her friend, but the screen had gone dead.

It was like her worst migraine had returned by an order of magnitude. The pressure inside her skull was grinding her thoughts to dust. Donna pulled uselessly at the device encircling her head. The thing wouldn't budge! _Transpositional Synaptic Repatterning Receiver_, something inside her whispered. Then her brain was full of fire and lightning.

She screamed until the world went black.

When she woke up on the basement floor, she wasn't alone.

* * *

><p>TBC<p> 


	8. Chapter 8

_**Previously:**_

"_It's not me that's holding it back. God, this is going to sound bonkers... There's a third entity in my mind now. A symbiotic consciousness that can neutralise the metacrisis for a time."_

"_But that's wonderful, maybe I can work out a way to make it permanent! What species is the consciousness?" He clapped his hands and grinned at her._

_Donna sighed. This was the part he wasn't going to like. "Time Lord."_

_The Doctor's face became suspiciously blank. "Sorry, what?"_

* * *

><p>"My symbiote... It's River Song."<p>

He flinched backward as if she had slapped him. "What?"

"I have your wife in my head and she's helping me. That's what is holding back the metacrisis now, keeping it from burning out my mind. She's building up my mental barriers, and redirecting the flow of energy so that it's in some kind of temporary stasis," Donna explained.

Biting at his lower lip, the bowtied Doctor shook his head in denial.

"Spaceman, say something. Other than 'what'." Donna paused to evaluate his face. He was looking at her like she had announced that she had decided to turn into a teapot. Maybe she _should_ slap him. She sighed instead. "Please."

"How did this _happen_?"

"You remember how Dalek Caan manipulated our timelines so that we'd meet? The same thing happened with me and River; fate caused our paths to cross again. We became friends without knowing who the other was. So when she found out, she convinced me to built this thing she designed. She said she could bring my memories back. Wasn't even sure it would work. But there was a chance, and I was willing to take it if it meant being whole again. It was the most important thing in the world to me and I didn't know why." Donna idly adjusted the vortex manipulator on her wrist. She could feel the weight of the Doctor's stare, and couldn't quite bring herself to meet it.

" 'S not like I had much else to do. Rich and bored and unhappy. Why not build a doomsday device as a hobby? A lottery fortune can buy quite a bit of black market alien tech, so thanks for that! Anyway, River's machine was a conduit to transfer her imprint from the Library computer onto some of the formless regeneration energy that makes up the metacrisis. But it's not like your memories, she's sort of independently active- like it was when I was inside CAL. Just that my subconscious mind is the storage now." She shrugged and smiled encouragingly.

The Doctor scratched at his cheek. "You downloaded River. Into your brain. She's in there with you."

"Yep. Here," she said, pointing at her head. Donna's eyes began to radiate regeneration energy, amber swirling over her customary blue. "Weeelll... specifically _c'est ici_. The closest human equivalent to a Time Lord's psionic locus." Donna's finger traveled six centimetres southwest on the ginger globe of her skull. She flashed the same brilliant, cheeky grin she had given him the last time she was on the Tardis.

"Donna," he said slowly and carefully, as if speaking to a sleepwalker. "It doesn't seem to be holding up very well."

The redhead blinked and the DoctorDonna personality she was unintentionally channeling fell away again. Her brow furrowed slightly over eyes brimming with questions. The unexpected lapse in River's defense seemed to remind Donna of her precarious state- the metacrisis could kill her. Seconds later, her deliberately airy smile was back in place. A brave face for him. Because of him. The Doctor's gut twisted painfully.

"Yeah, this arrangement ain't exactly an ideal solution. Miss Noble's Hostel for the Temporally Displaced is full up," she said in a teasing tone. "But it's working for now, and that's what matters. When River saw the metacrisis energy from the inside, she said that-"

The Doctor interrupted, his voice quiet but intense. "Does she... talk to you?"

"Yeah, I can hear her sometimes. Bossy, never gives proper answers, inappropriately _flirty_ during times of danger. Sound familiar?"

The Doctor leaned forward. "Hello River, can you access Donna's primary auditory cortex? Are you able to communicate through her?" His voice rose like he was speaking to someone across the room and not a ghost buried within a foreign brain. "I need to know more about the neural overlay pattern you used so that I can lift it out intact. I mean, I could guess at it but that might be... nevermind. Oh, right. This is the Doctor speaking! Thank you. Bye!"

"Oi! I'm not her bloomin' ansaphone, you prawn, so quit shoutin' in my face!"

Looking suitably abashed, he whispered cautiously, "Is she saying anything now?"

Donna sighed. "No, sorry. I think she's been busy using all of her willpower in corralling the metacrisis." Her stare lost focus in introspection. "Tho' it's not really like a voice when she does talk. More like thoughts that just come to me, like a stray memory or something, but they're not mine. It's all symbolic like in dreams."

"So the additional consciousness is fully manifest and at least partially tapped into the limbic system. Good, I can use that. Going to try to bypass um... _you_, sorry... and contact her telepathically."

The Doctor reached his right hand towards Donna's forehead.

"No!" Instantly, her own right arm snapped up to grab his wrist in an overhand grip, her thumb biting into the soft tissue between his thumb and index.

In one fluid motion she rotated her arm from shoulder level down to her side. His trapped wrist was forced to follow, wrenched across his body, twisting beyond its normal range of motion to the point where his elbow was locked. A tiny bit more torque and one or more of the Doctor's joints would break. Her other hand had a death grip on his right shoulder.

"Now, now, none of that," purred the redhead. There was something off about her voice.

The Time Lord tore his gaze from his ensnared limb to Donna's face. Her eyes were shining with golden regeneration energy once again.

"D- Donna?" The Doctor regarded her angled brows and tight smile. He had never seen this expression on his companion's face. Donna could be shouty and stroppy, but never _aggressive_. His green eyes widened in recognition. "River?"

A tug on his wrist propelled the overbalanced Doctor forward into a warm female body. Then she was kissing him.

"Hi, honey, I'm home." River Song's low, musical laugh emerged from Donna's throat as she appropriated his line. "I've been waiting a while to do that. Ok, either kiss you or slap you. And I won't tell you Donna's vote on the matter." She winked a glowing eye and released his wrist.

"How is this... She was never... There's no..." The Doctor steadied himself against the Tardis console, thankful for something solid and familiar.

"I'm going to have to insist that you stay out of Donna's mind," said River pointedly. "You need to trust that I have this under control. The regeneration energy is contained for now, but it's a delicate balance. You're not barging in during a fit of reactionary heroics."

"I don't do that! My heroics are extremely helpful and, and... well-reasoned!"

Seeing the hurt look on his face, River was quick to offer a distraction. "The overlay I used was patterned based on Gallifrey Matrix schematic 445/Omicron. Modified for Human Plus but still stable. It will be fine. But I can't be at the surface long, so I'm going to _trust_ _you_ to let me handle this."

The Doctor nodded numbly and the golden light began to fade from the woman's eyes. "Wait, don't go yet!"

"What is it, sweetie?"

"You _died_. And I saw it and I could never say anything. To you or to your parents. I tried everything though, after it happened. Please believe that I tried... I've done all the maths, ran countless simulations. But I couldn't save you any more than I could save Donna." The Doctor ghosted his fingers along a lock of red hair, then pulled back his hand as if burned.

"I know," River replied gently.

"Darillium was... a while ago for me. And Donna, it's been so long since I had to leave her. Lifetimes. Not mine, but someone's. 316 years, 4 months, and 23 days in my personal timeline. Well, that's counting you both separately but I think I've earned the right to mark time however I please, haven't I?" the Doctor asked, his eyes downcast.

"And you've been carrying the guilt ever since."

"Of course. Regret is a major component of the missing-and-remembering package."

River took his hand and wove her fingers through his. "I have just the thing for that."

"What?"

"Today you help free us," she said with a feigned carelessness.

"But I- oh!" He grinned and tapped her nose. "You bad, bad girl. A Gallifreyan matrix overlay? Those can be extricated undamaged if you reverse it along the same pathways exactly." The Doctor dashed over to the console and began to noisily clack away at the typewriter.

"No, Doctor, just assist Donna. She can tell you the plan. There's work to do right now, plenty of time to talk later. I have to return to the subconscious before the metacrisis gains more ground. A girl could get used to this body, but I'm afraid it's only a loan." River ran her hands down her host's curves. The golden light was replaced with Donna's blue irises.

"Oi, that is your _last_ warning about _hands_, Timehead!" Donna shouted indignantly at the ceiling.

The Doctor failed to stifle a giggle.

Not having a proper target for her ire, Donna shot a blame-laced glare at the Doctor. He opened his mouth to protest, but quickly shut it upon remembering the kiss. With his wife. Using Donna's lips. Those lips were currently pressed into an thin, angry line as she stomped toward him like a ginger juggernaut. Apparently Donna could remember the kiss as well.

No point running; the Tardis would just lead her right to him. His hands flitted about nervously as he tried to think of a way to placate her. "Your lip gloss tastes nice?"

Donna mouth formed an O as she made a scandalized squeak. She closed in on him. The Doctor wondered if any Time Lords had ever been slapped into their next regeneration.

"Strawberry, is it?" he ventured. "Better than anchovy like the last time you kissed me."

The force of her palm against his cheek made the Doctor whirl around in almost a full circle as his boots slipped on the glassy floor. The Time Lord rubbed at his aching jaw. "Blimey! You're even better at that than before. You don't _practice_ slapping do you?"

"Course not. Naturally talented." Temper subdued, Donna now favored the Doctor with a winning smile. "I believe my counterpart said to get to work."

* * *

><p>TBC<p> 


	9. Chapter 9

The Doctor raced around the console in a mad flurry of activity.

"Shouldn't we talk strategy first?" Donna called after him. "I haven't even-"

"No need! River, you'll be safe enough in the Tardis memory storage. I'll do a thing and transfer your pattern there! And as for you, Donna..."

"Doctor," she protested, trying in vain to divert his attention.

His voice became muffled as he disappeared under the console and started rummaging. "Everything can be wiped from your memory again. I'll do a better job this time, I promise. Give you a memory of a long holiday in Greece instead of blank spots. You'd like that, wouldn't you, Donna? Maybe New Zealand. Love a kiwi! I can fix this. Do it properly this time. Everybody back where they're supposed to be, everyone safe."

She followed the Doctor to where he had half-crawled under a section of the hexagonal dashboard. All that could be seen of Time Lord were his bandy legs. She loudly rapped her knuckles on a Perspex panel engraved in pattern of concentric circles. "Oi, Doctor! I am tryin' to talk to you."

Donna looked down at his ankles, where a ring of pale skin ran between his socks and the ends of his rolled up trouser cuffs. She considered dragging him out by one of them. A harmonica flew out from under the console, barely missing her knee. She dodged further to the side when it was followed by part of a charred manual, a skateboard wheel, and a barrage of fuses and batteries.

"Ha ha! Yes, you clever little thing. Perfect relay for memory transfer." The Doctor emerged from under the console, holding something aloft triumphantly. He wiped his other hand over his brow, leaving a trail of black smudges. Producing medical electrodes from a pocket, he began to attach them to the contraption he had retrieved from under the console.

Donna eyed the apparatus he was holding and stepped back a few paces. "God, I thought you were hyper before! Can you just _stop_ for a minute?"

The Doctor slowed. He absently pulled up one of his braces that had fallen loose against his leg. For a moment he looked like nothing more than a lost little boy, but just as quickly it was replaced with a look of implacable resolve. A muscle clenched in his jaw.

"There isn't time," he hissed as he advanced on the redhead. "Over here." The Doctor extended an arm around her back, and though not touching her, tried to herd Donna over to the monitor hanging next to the time rotor. When she didn't move, he mimed a hurry-up motion that swayed the electrodes dangling from the thing he carried. "Donna. I won't hurt you, not ever. Just do as I say."

She smiled sadly. "Ok, Spaceman. I know you just want to help. Is that a Neural Phase Override? I read about them when I was building the transfer circuit." Donna held out her hand for the grimy metallic whatsit.

The Doctor's face softened. Not one to pass up a chance to show off a bit, he grinned and gave it to her. "A Mark II, in fact!"

"Those are nearly impossible to obtain, and for good reason," replied River's dangerously cavalier voice as Donna's eyes blazed gold with luminous energy. "Unstable, illegal, plus the fault that can trigger implosion. Not that doesn't sound like a good time, but..."

She tossed the device on the floor and casually crushed it under her heel.

"No, no, no!" The Doctor dropped to his knees and attempted to gather up the shards of the broken Neural Phase Override Mark II. An acrid smell filled the air as crackling blue sparks burned out the remaining circuits. The Doctor looked up at the face of his former companion mournfully. "Oh, _River_, what have you done?"

"Only what I must. Donna and I have a plan, but we need you to listen."

He clambered to his feet clutching a fistful of gears and wires to his chest. The Doctor's head was tipped forward, hiding his eyes in shadow. "But now you're going to be trapped inside Donna's mind when I suppress the metacrisis again."

"You are not doing any such thing." Though soft, River's voice held an edge of promise to it.

"Nothing has changed, there's still no solution. There's only another chance to reopen old wounds." The Doctor's voice was barely above a whisper. "What is this? Why are you both back here? Couldn't you leave well enough alone?"

"Not in my nature." Her gaze twinkled with pulses of regeneration energy, making it difficult to read her expression. River reached out to straighten his bow tie, an action she had repeated countless times, but the Doctor stepped out of reach. He folded his arms around himself protectively.

"So just popped in for some banter, did you? How thoughtful." His green eyes were cold. "This isn't like Stormcage where you can escape for a lark. If you haven't considered the gravity of the situation, Professor, here it is: you'll die and so will Donna. I'm not going to let that happen. Stop being difficult and let me get on with it. Then I'll spend the next hundred years wishing this day never happened," the Doctor said an in artificially breezy tone.

"It's going to be-"

"Don't you dare tell me it's going to be _fine_, River Song!" he roared. "How could it? We'll all go right back where we started, except with fresh memories to feed my nightmares. I'll make it so that you both forget. Oh, but _me_... I always remember. It was hard enough moving on the first time. Can't you see how coming back like this- talking, laughing, _alive_- is twisting the knife?" The Doctor's voice broke. "Making it all fresh again. I'm losing Donna and you all over again."

The Doctor collapsed into the jump seat. Blinking rapidly, he busied himself with poking at the electronics innards he was still grasping. Irreparable and irreplaceable.

River slowly released the breath she didn't realize she was holding. "I'm sorry, my love. My intention was never to hurt you. But we won't be packed away into storage like broken dolls. Either we'll be free or we'll die."

The yellow glow faded from the woman as Donna resumed control of her body. She gently rubbed the Doctor's thin, tweedy shoulder. "Shh, 's alright."

The Doctor tried to swallow the emotion that threatened to choke him. "Donna... I c- can't do this again. It's too m- much. Why would the universe bring you both back to me, just so that I can say goodbye and then watch helplessly as you combust? It's better the other way, like it was before. I've been so, so alone. But at least I knew my Donna and my River were still out there, _safe_, even if we couldn't ever... And now you're here, _trying_ to burn up? Why?"

Donna snorted. "You're seriously askin' me _why_, you berk? You already know. The fates you chose for me and River are the last things we'd ever want. You know we would have both wanted to die instead of being, I dunno, made into _shadows_. Something less. I can understand what happened with River. You didn't know who and what she was back then. For an average person the CAL hard drive could have been a paradise, but for her it was another prison. But me..."

He shifted uncomfortably. Donna towered over the Time Lord, fists on her hips, magnificent in her anger.

"You knew me. How could you think it would be ok for me to return to that life, that Donna? The Donna from before my eyes were opened to the universe?" she asked heatedly. "A colourless existence with no dreams and no memories. And even if you were that thick... Doctor, I _told_ you. You looked into my eyes and flippin' ignored what I wanted. Imposed your will on my mind. What that would have been called on Gallifrey... How dare you!"

The Doctor sunk further down on the jump seat, his misery palpable.

"And afterwards, I was so unhappy without knowin' why, until the Timehead and I found each other." Donna tilted her defiantly. "Now we're going to have a say about it."

"I couldn't just let you die because of me, not when I could prevent it. Don't care if it's selfish." He wound his arms around the redhead's waist and pressed the side of his face to her belly. "It had to be done. I'm sorry Donna, but it still has to be done."

She smacked his arm. "Stop choosing for us! You don't have that right! And you don't always know best. There's the Doctor's way and then there's the wrong way, innit?" His grip around her middle tightened, and Donna relented with a crooked, compassionate smile. She lightly smoothed her hand over the Doctor's floppy hair. "Try not to take responsibility for everything. I see the pressures you face... got a bunch of that knowledge tucked away in my head. The Doctor in the Tardis, forever running from the pain and guilt of what you've had to do. Well, it's not all your burden to carry."

He still had streaks of motor oil on his forehead from his foray under the console. She fished a handkerchief from his breast pocket and wiped them away. "No sense in telling you to accept that death is part of life, I s'pose. But what you _do_ have to accept and respect is my decision. If we don't have free will, what are we other than puppets?"

The Doctor released her but just sat there limply. All of the nervous energy from earlier had drained from him, leaving behind something ancient and fragile.

Donna broke the silence with a peal of laughter. "Oh my god, is 'adorable contrition' the first look you perfect in every regeneration? You're lucky I already forgive you, cos that does _not_ work on me. Or on her, for that matter." She tapped her temple to indicate her symbiote.

The Doctor's mouth worked soundlessly for a moment before he managed to say, "You do? Forgive me?"

"Of course. Come on, up you get. Allons-y, or whatever rubbish you say now."

Taking his hands, Donna hauled the Doctor to his feet. Neither of them made a move to release the other. The smile that flickered on the Doctor's face was tentative, but it was genuine.

"Now you're going to listen, you daft alien. We keep sayin' that River and I have a plan to deal with the metacrisis. In your mind you've got me set to explode into flames, but you haven't even heard what we're going to do yet. I didn't come all this way just to yell at you and then die!"

* * *

><p>TBC<p> 


	10. Chapter 10

"So, this plan." The Doctor bounced a bit on his toes. "Let's hear it."

"River had a dig on a planet where there had been a small society of people with technology that could separate or combine different minds within the same brain. They believed that the body is just a tool or transport. Something naff you wear 'round the house on a Thursday evening. It's not who you are, cos all you really are is your thoughts. So they swapped consciousnesses as a religious rite or somethin'. Used it for loads of things, like as a getting-to-know-you, or learning compassion by walking a mile in someone else's shoes. Apparently it was like a physical form of telepathy for those of us without the natural ability." Donna sniffed. "Poor sods, imagine what their marriages were like. Is that what it was like for Time Lords? Come home one day and your husband is some other man? Or a woman. Did that happen? Cor, that would keep things interesting."

"Donna!" His offended countenance was less effective when he was trying to clamp down a giggle.

"Sorry," she said, completely unapologetically. "The team found traces of a lost temple where this would have happened. That wasn't the focus of their expedition, so they left it uncovered for later. We should be able to get what we need from those ruins. Or from the people if we, y'know, go visit them before they died out. Need a scanner thingummy and holding vessel. It's an organic brain analogue, River said. Then her template can be programmed into a Flesh avatar without an original body cos the vessel will read as alive. You'll have to sort that part."

"My ship is at your command. Where are we going first?"

Donna punched a few buttons on the vortex manipulator, then held up her wrist up so he could read the coordinates on the small, green display. The Doctor blinked, the tiniest of expressions, but the redhead noticed. He then immediately favored her with an affable smile.

"That is... Falxia Meridiem, 7th century of the Cantalvion dynasty! Easy peasy." He laughed in his staccato way and stepped over to the console.

Donna lounged against the platform railing, enjoying the first peaceful moment since she had arrived. She watched the Doctor at work. Flipping a toggle switch with an elbow, plugging his sonic screwdriver into the dashboard with a flourish, then twirling around to dial in a complicated pattern of buttons. He was clearly pleased to have an audience, as Donna knew he was flying the Tardis in a manner more flamboyant than necessary. When so many of the details had changed, seeing the Doctor in his element was soothing in its familiarity.

Something _itched_ at the edge of her perception, like the whine of a mosquito near her ear. Donna tossed her head in irritation but tried to ignore it. A new Tardis interior could mean new sounds. It was getting louder, now an audible droning hum that set her teeth on edge. It modulated in pitch, never staying the same for more than a second. She looked around but couldn't pinpoint the source. The buzzing was equally loud from all directions.

"Is this weirdo alien music? Are you into dubstep now? Cos I don't fancy a concert from DJ Bleedin' Bowtie at the moment! Only dogs could hear the whole thing properly," Donna complained over the din.

The Doctor paused and looked up from where he was bent over the typewriter. Craning his neck, he peered around the room. He gave her a cheery thumbs-up and went back to work.

The mechanical whalesong of the Tardis in flight was overpowered by discordant screeches. Donna thought the usual vworp vworp landing noise would be like angels singing next to this racket. She could _feel_ it in the soft tissues of her throat and gut; even the railing behind her was vibrating under the force of the sound. She stuck her fingers in her ears and bellowed, "DOCTOR!"

"Wait, don't cover your ears," she saw the Time Lord mouth as he bounded over. He stuck his hands out in front of him, palm up, in invitation. She reluctantly took her hands away from her ears and winced as sound seemed to flow directly down her brainstem. "I'll turn it down." He aimed the sonic over his shoulder and the noise reduced to a tolerable level. It was now just one constant tone.

"What was that?"

"Just had to triangulate your position and find the right frequency." The Doctor pointed with false modesty at one of the round metallic things embedded in the coppery Tardis wall to her right, then another one on her left side. "Speakers, among other things."

"You did that on purpose!" Donna swatted at him halfheartedly. "Thanks for the warning."

"Sorry, couldn't tell you before, cos it had to be unexpected. We've got some privacy now. Sound's blocking any little eavesdroppers on board," he said as if the prospect of spies were rather thrilling.

"There's only just us here." Despite knowing this, Donna glanced down the hallways that lead further into the heart of the Tardis.

"Wasn't counting noses, Noble." He drew a little circle on her forehead with his fingertip, then tapped the center of it.

"River? What do you have to hide from her?"

"Nothing. Everything. Just need some time." He frowned, picking at some imaginary lint on his sleeve. "It's... complicated," he amended finally.

Donna rolled her eyes. "If you're gonna be like that, I'll just go sleep off the headache _you_ gave me with that stupid noise." She started turning to leave, but the Doctor blocked her path. The concerned look on his face stopped her short more than his physical presence.

"Don't go! It's important that you stay still, exactly here. Just for a few minutes so we can talk."

"Why? What's so special about this spot?" She raised an eyebrow at him but returned to her original position.

"It's not, it just happened to be where you were standing when I calibrated the signal. The speakers on either side of you are aimed directly at the corresponding ear, creating a localised auditory field. Like headphones. Each side is playing a separate frequency, but the human brain blends them together into a single wavelength, so it sounds like you're only hearing one tone. They call it binaural beats in your time. The neural oscillation I set up here is canceling out the gamma brain waves linking your conscious mind to the subconscious. River is alright, but she'll be deaf and blind... and probably very very cross."

"There's a safe bet, sunshine. Assumin' you have a reason for the cloak 'n dagger, how d'you know it worked? I don't feel any different except for the buzzing eardrums."

"Mm. Going to try something. Quick test. Let me know if you feel her react. Though I'll probably be able to tell because of the violence." He unfolded some red fabric from his pocket. Moving with deliberate care, the Doctor placed a fez on Donna's head. "Anything?"

Donna struck an exaggerated fashion model pose. "Does this mean you're finally takin' me to the Planet of the Hats?"

The Doctor's eyes lit up. "I could get one of those fuzzy ear flap hats. A ushanka. Those are cool," he said longingly. "Nah. Stuff to do first. There's always stuff. I'm fairly sure that River is cut off or she'd have something to say by now. May I have the manipulator?"

Donna removed the wrist strap and handed it to him. Bleeping it first with his sonic, the Doctor squirreled the cuff away under the console in a drawer that wasn't there a minute ago. He retrieved something from the hidden cache and slipped it in his jacket pocket. When he turned he saw Donna watching. "Preparing for the fallout. As much as I wish... You were right. I can't control what's happening here. But maybe I can guide it a bit, minimise the damage." He glanced at his gold wristwatch and frowned. "Breakfast time in England. No one likes tears before they've had a nibble in the morning."

She slumped back against the metal bar. "You sound like you still think this is gonna fail. Like I'm just doomed. I spent six months working for this chance and it's not even worth trying."

"No no, it's not like that. I promise. I'll do anything to save you, no matter what. Trust me?" The Doctor pulled Donna into a hug, where he felt her nod her agreement against his shoulder. "The thing is, your plan's rubbish."

"_What?_" She pulled away from him.

"River was adamant that I not get a peek inside your head." The Doctor dropped into a stage whisper. "Why do you suppose that is?"

"She- she said it could disturb the balance she had struck against the metacrisis energy." Donna could barely hear her own voice over the drone of the speakers and her own insecurities screaming in victory.

He laughed, a drawn-out haaaa. "The first thing you should know about River Song, or the first rule if you prefer, is that she _lies_. What she told you about a scheme to resolve the metacrisis with an artifact and get herself a new cloned body. It's a ruse. Wouldn't work; not even _meant_ to work."

"How can you be so sure?"

"Her diary. I may have, um, read it. After Darillium there were no more spoilers, so I didn't see the harm. Other than her killing me when she finds out. The risk of that seemed _really_ small at the time!" He gulped. "She documented her whole life in that book. Everything. She couldn't have been on an archeological expedition that turned up a convenient mystical consciousness-separating relic on Falxia Meridiem. River's never been there."

The redhead's face flushed with anger and betrayal. "This whole time she was just connin' me? Havin' a laugh at dim old Donna? I thought she was my _friend_. If I manage to get her out of my brain and into a solid body, I'm gonna kick her arse!"

"Oh, Donna. I didn't say your friendship was fake." The Doctor caught one of her clenched hands and awkwardly petted it. "Just the method of getting you here. River's always had her own ways of accomplishing a goal. Likes to take shortcuts through the grey areas. It's clear she cares for you a great deal." The tension in Donna's arm reduced somewhat.

"Before my memory was restored she could have told me that there was, I dunno, a clinic in Sweden that specialised in neural pathway reconstruction, and just popped over here instead. If all she wanted was to get me back on the Tardis, she could have dropped the act at that point. There's something else, just not what she told us."

"That part was for my benefit, I'm afraid. Wouldn't be surprised to find myself temporarily stranded on Falxia as soon as I walked out the doors. Put the Doctor where he can't interfere. Cos she knew I would. Or I _would have_, before you talked me out of it." He took a great breath that was almost a sigh. "Now she must know that I know. I know that she knows I know, and she knows that I kno- This is going to get repetitive. Let's switch the metaphor to seeing chess moves ahead. No, no. I hate chess. It's boring when there's no voltage. Are you at all familiar with the Royal Game of Ur?"

Donna was glaring at him. "A point. Are you ever able to arrive at one?" she asked in clipped tones.

The Doctor appeared to feel the burden of every one of his 1600 years, his head sunken to his chest. "I know what River's doing now. And I'm going to let her."

He approached the console again, flicking switches that brought the glass bauble of the time rotor to life. There was a slight jolt as the Tardis landed at her destination.

"Donna, I'm sorry. You can't share a body with two other consciousnesses, it's not stable. The metacrisis can't be removed. River can't be transferred out in the time you've got left. The only way that everyone survives is to wipe your memory, which you both refuse. When I said before that there wasn't a solution, I meant it. There's nothing I can do." The Doctor's brow furrowed. "But I think River found a way, if she lets the metacrisis go and channels the energy."

"You said I'd burn if that happened."

"And you would have done. The human mind wouldn't be able to cope. The metacrisis is a fragment of regeneration energy lodged in your head. You wouldn't know what to do with the power that's unlocked. It would try to rewrite you entirely, replacing your mind with the merged copy of mine. River's part Time Lord. Regeneration is instinctual for us. She could direct the power, use it up. You'd be fine." He smiled, but it didn't quite reach his eyes.

"That sounds like a good thing. I would like to live, y'know. But you look like someone stole your sonic and made you eat a pear. You're not tellin' me everything, Spaceman."

The Doctor dragged his fingers through his hair. For a moment he was silent, seeming to weigh his words. "River's consciousness will be consumed along with the metacrisis."

There was a knock on the exterior of the Tardis doors. "Hey, Doctor," a female voice called from outside. "Want to join us for breakfast? Rory's cooking omelets."

"But she doesn't have to do it alone. Old Girl, be a lamb and let the Ponds in, won't you?"

The Yale lock clicked itself open.

* * *

><p>TBC<p>

A/N: Sorry for another cliffhanger- this was supposed to be the last chapter, but it kind of got away from me. Thanks for your patience :)


	11. Chapter 11

"Stay put for just another minute," the Doctor cautioned Donna as another former traveling companion swept through the double doors. Rory and a young man followed in Amy's wake. "Hello, Ponds."

"We don't have got any chocolate drops in, so if that puts you off an omelet, there's also toast with mustard and jam." Amy's face made clear what she thought of the Time Lord's eating habits. She spotted Donna and grinned, though it held no recognition. "Oh my god, you've found a friend who's fond of a fez- I owe someone a tenner! Hey. I'm Amy. This is Rory and Jules." She pointed to the two men, one of which looked like a shorter, more ginger version of the other.

"Donna. Donna Noble." If Amy was kind enough to pretend the garden incident never happened, Donna was happy to play along.

"You're welcomed to breakfast as well. Have you been with the Doctor long? Has the _'it's bigger on the inside'_ thing worn off yet? He loves that phase, the old rogue."

Donna glanced at the Doctor. He was studying his bootlaces. " 'S been sort of... on and off again. Though the way I met him, it was more like the Tardis was smaller on the outsi—"

"I know you!" Amy bounded up the stairs to approach the pair on the far side of the platform. Closer up, Donna could see that the other woman was significantly older than when they had met. Amy was her elder this time. "I remember now! You ran off with River's vortex manipulator. Nice to see that you didn't get splinched or something using that thing."

"That was awkward, wasn't it? Not at all like this." Donna laughed, the sound high and false in her ears.

"Don't worry about it. We always wondered what happened to you. Always meant to ask, but got kind of sidetracked when Julian came along. I was pregnant with him when we met." Amy threw an arm around the young man to ruffle his hair. His long-suffering expression spoke volumes of the average teenager's struggle with an embarrassing mum. Smirking, she gently pushed him in the direction of the upper staircase. "Go find that virtual reality room you're always on about. And if you programme somethin' with girls, try not to make them evil geniuses that attempt take over the ship this time," she called after her son, then turned back to Donna. "Off to university soon."

Despite her nerves, Donna managed a heart-felt smile. "How wonderful, you must be very proud."

"Over the moon. But they grow up so fast. You never have as much time as you hoped." Amy's voice was sunny, but the lines around her eyes drew together slightly. She shrugged, as if to banish a thought, and her expression returned to what seemed to be a customary wry smile. "Do you know our River?"

Donna coughed. "Erm, yeah, really well actually." She nudged the Doctor in the ribs, but he failed to respond. Fine, he was going to leave her to twist in the wind. "Two peas in a pod, that's us. Very close."

" 'Really well,' eh?" Amy was eyeing Donna shrewdly. "Are you married to them? Is there some spacey-wacey polygamy afoot in the Tardis? Are there His, Hers, and Hers towels up in the loo?"

Rory and Donna's immediate, overlapping protests filled the air.

"Oi, 'm not married to _any_ flippin' Time Lord!" Donna huffed. "Do I somehow, I dunno, _exude_ signs that I belong arm-in-arm with every Martian that comes to call?"

"A shame. I always thought River could do with a wife. She shrinks everything when she does the wash and her coffee is swamp water," the Scottish provocateur teased.

"Amy," groaned her husband. "Yes, I am aware of the cultural differences between our time and the 51st century, but you don't have to _actively_ bring up... things... a father does not need to know." He turned to address Donna. "Not that you're not lovely. I'm sure that you would be an asset to any multiple partn—" Blushing, Rory quickly spun back to Amy. "But _seriously_. For the sake of my sanity."

Amy mock-pouted. "Okay, okay, only for you. Best behaviour."

Rory's distress faded as he gave her a loving smile. They had spent more than half their lives together, but Amy could still melt his heart like it was Auton plastic. He noticed something during the lull. Or rather, absence of something. The Doctor never went this long without speaking. The lack of techno-babble was eerie. "Doctor, will River be along soon?" Rory asked the unusually subdued alien. He gestured at the hallway entrance with a thumb.

The Doctor finally stirred. "Your daughter is... where she's required. My wonderful, brave Ponds! The Woman Who Remembered. The Duke of Jumpers." The Time Lord hugged each as he named them. "We need to talk about River."

"If she's not here and she doesn't have her vortex manipulator- Don't tell me you left her stranded somewhere, Doctor," Rory said disapprovingly.

Amy made a dismissive noise at her husband. "You're so overprotective. River can take care of herself. She always has done."

"Last time she visited, she said she'd been freed from Stormcage, but that was ages ago. I thought we'd see her more often, not _less_. They're time travelers, Amy. They could be here every day if they wanted. So where is she?"

The Doctor hesitated, shifting his jaw sideways in thought. "We were in the Library. A whole planet of nothing but books from a hundred worlds. But the books were full of as many shadows as words, and the shadows tried to consume the readers."

"Sounds like a fairy tale," Amy murmured.

"Then you can appreciate the danger." He regarded her solemnly. "All of the survivors were saved inside the Library's hard drive, but it was failing under the strain. The whole planet was going to self destruct. River stopped it, got all the people out. At a terrible cost. I- I tried to do it myself. She knocked me out. Handcuffs. You know River Song." His breath caught. Donna slipped her hand into the Doctor's, holding it like they were running together. No running this time; the monsters already won. "Her body was destroyed, but I saved her thought pattern. I'm so sorry. That's all that's left."

Amy's face was wooden. "No. No, no, no," she repeated. Rory caught her against his chest, where she sagged, muttering denials into his shirt.

"She's only _thoughts_ now? What does that _mean_? I don't even— How? When?" Rory's demand was hardly more than a whisper.

Donna spoke up before the Doctor could reply. "I was there, too. The Doctor saved her consciousness in his sonic, and now I have it stored in my head. She's here, with me." No harm in fudging the timeline of events for her family's peace of mind. Let them think it just happened. There was no answer he could give that wouldn't end with the Ponds hating him for hiding their daughter's death from them for the last 35 years, spoilers or not. The Doctor deserved some of their anger, but it was cruel to let Amy and Rory know all of the details.

She remembered River saying something about getting to be as bad as the Doctor. Donna could see how his way of doing things was easier. Tell people what to do for their own good, because explaining was just... too painful. This was exactly his type of well-intentioned lie that he had no right to make, and here she was doing it in his place. She half expected the Doctor to say something, especially since she had just raked him over the coals about allowing people their own choices, but he just moved slightly so that their shoulders were touching. A gesture of solidarity.

The hope blossomed on Rory's face. "You're- you're River in a new body. Like regeneration but with a flatmate."

"Ponds," said the Doctor gently, "it can't last, this arrangement. Time is running out. She's going to regenerate, but only Donna will be there after. I can't bring your daughter back to you. All I can offer is time to say goodbye."

Amy rubbed the back of her hand over her eyes. Sniffling slightly, she straightened her clothing and hair. "Let's get on with it, then. If this is all we get, I don't want to waste it." She smiled bravely at Rory.

"Um, step back a pace everyone. She may be just a smidgen_ peeved_ that I locked her in the limbo of Donna's subconscious. Probably little gooey bits of id floating around in there." He wriggled his fingers to illustrate the unsavory regions of his companion's brain, until Donna smacked his upper arm. The Doctor took his own advice and retreated to a spot where he could use the console as cover.

A whirring signal from the sonic disabled the wall speakers. As soon as the drone of the binaural beats died, Donna's eyes began to seethe with golden regeneration energy. The light radiated as if from twin blast furnaces, raining down photonic embers that sparked fitfully on the glass floor. Her body staggered forward with the force at which the symbiotic consciousness became the dominant personality. "_Doctor!_" she growled in the voice of River Song.

Instead of the expected face of the Time Lord, she saw her parents waiting at near-hovering distance. "Oh, I hate you, Doctor."

"You don't," he responded confidently from his near-hidden position on the far side of the rotor.

"Mum, Dad, lovely to see you. Am I wearing a _fez?_ Hold on while I kill my husband." She tossed aside the offending headwear and stalked around the console, but the Doctor slipped down the other side to join the Ponds.

"Oh my god, it is her," Amy said quietly.

River paused to really look at their faces, their body language. They seemed shocked, confused, and worst of all, scared. "You know. You all _know_. What's going to happen." She breathed out as though her anger was deflating. "They aren't supposed to be here, no one is."

"I know. You were going to leave me on Falxia Meridiem so you could take the Old Girl into the vortex and regenerate there. Alone. Programme her to return automatically when the deed was done."

"My parents- They've had enough trauma for this lifetime, quite a lot of it being my fault. They don't need to witness this on top of it all. You shouldn't have brought them into it." Though she didn't say it, River's _'they'_ clearly included the Doctor as well.

Rory spoke up. "River, sweetie, we _want_ to be here for you. I'm glad the Doctor included us." He and Amy embraced their daughter in a group hug.

The Doctor made a hesitant move as though he wanted to join, but then restrained himself. "Alright. So, hugging and imminent crying. I'll go fetch the missing Pond, shall I? Where did Julian wander off to? Ah, one of the VR suites." He dashed up the stairs and disappeared.

"Wait, isn't that thing like a holodeck or something?" Amy asked. "The Doctor was able to hold your mind inside the sonic before. Maybe you could go into one of those suites instead of regenerating!"

"No, Amy. I'm sorry but I can't," River said firmly.

"That _can't_ sounds like _won't_, Melody Elizabeth Pond. You could at least try it until the Doctor thinks of something."

"You don't know what you're asking of me. My answer is no." River shook her head. "Your daughter died in the Library. I'm her data ghost, an echo of the person I was. Even now as a symbiotic consciousness, there's not enough left of me to exist on my own. I'll never have full autonomy again. Can't live like that, Mum, regardless of the cost. I will not be imprisoned again." The yellow light in her eyes intensified.

"It's not like you to just... give up."

River grinned. "Never. This is my choice, and I made it months ago, before Donna and I started to build the relay to transfer me out of the Library. My half-existence can be traded in to give her a full one. Let me do this for her. But it has to be here and it has to be now."

Rory and Amy exchanged a look laden with emotion. He nodded in acceptance, and a second later so did she.

Julian arrived back in the control room at a run. He launched himself at River in the hug-tackle of an adolescent not quite used to his own strength. She, like her mother earlier, ruffled his hair affectionately, but this time he didn't seem to mind. The Doctor arrived right behind Julian but remained at the top of the stairs. He watched the little family below, feeling a bit like an intruder in his own home.

Amy caught his eye and beckoned him over with a tilt of her head. "Come on, you numpty." Bouncing a bit, he joined the reunion.

After a few minutes, River managed to extricate herself from the other Ponds to speak to the Doctor. She smoothed the Time Lord's bow tie. "Thank you. I didn't realize that I needed this kind of closure. It's quite annoying when you're right, you know."

"I've been made aware that most things I do are irritatingly clever." The Doctor peered into her face, searching for something. "The regeneration field seeping from your ocular cavities has been increasing by 15% every five minutes." He picked up her left arm by the wrist and studied her fingers from every angle. "Your hands are shaking. Have you noticed?"

River rubbed at the crown of her head, momentarily thrown by the difference from her normal hair texture. "Don't know how much longer I can hold off. The metacrisis energy is fluctuating outside of my ability to control. At some point it will breech the barriers. There's something we haven't discussed, but I know you've considered the possibility." She leant forward and whispered something in the Doctor's ear.

"Really? Are you sure?" the Doctor said squeakily. "I think I may be able to help you with some of the more fiddly genomes if you wouldn't mind. Simple biological transfer should do the trick."

"Ever the romantic." She chuckled, but it was cut short when clouds of regeneration energy escaped along with her breath. "Perhaps it should be sooner rather than later. I need the Tardis to stabilise stabilise stabilise stabilise—" She clamped a hand over her mouth to stem the flow of words. When she finally removed it, River's familiar smirk tugged at Donna's lips. "Best hurry," she said dryly.

The Doctor moved to the console and piloted the Tardis into the time vortex with a few well-practiced motions. He shooed the Ponds back to a safe distance.

"Mum, Dad, Jules. Doctor. Donna. Love you all." River's hands were beginning to blaze as vibrantly as the golden light dancing in her eyes.

The Doctor approached the glowing woman. "Thank you for this. I'll never forget."

"Oh, shut up," she teased and then kissed him. Regeneration energy poured from her head and hands like roman candles. There were tinges of silver within the gold. Somehow River was augmenting the metacrisis energy with rift energy channeled from the vortex, making it stronger.

He could feel her DNA mutating under his touch. Double helices splintering and re-encoding, tempered in the fires of change sweeping through her body. The energy stung his skin, alternatingly hot and cold, but he held on. He remembered what River had whispered to him. _"Sweetie, it's time to move on. I've always known that some day our time would run out. I could never have _Forever_, but it is a gift I can give to someone else. Donna wants to be with you for the rest of her life. I can make her a full Time Lady- you won't ever have to be lonely again."_

The woman jerked backward with a gasp as the regeneration cycle completed. Almost afraid to open his eyes, the Doctor whispered, "Noble?"

"What," Donna demanded, "did you misunderstand about gettin' fresh with me, mister?"

"Donna!" His eyes popped open to gawk at his best mate. She looked the same, but his senses could pick up her distinct double heartbeat. He stuck his head close to her hair. She smelled... Time Lord!

"Gerroff, you weirdo!" She pursed her lips. "Blimey. I'm the same type of outer space whatsit as you now. That's brilliant! Now you're going to have to show me everything this universe has to offer. There's a lot to see; I'm thinkin' one galaxy per decade." She glanced over at the family waiting at the other side of the room. Donna's excitement gave way to empathy. "But first we should spend some time with the Ponds. Help 'em. Be there for 'em. I want to- well, I want to prove my worth. Show her parents that I'm deserving of the faith everyone's had in me."

"You're a Time Lady for two minutes and you already have a plan for the universe. You don't have to prove anything. What was given to you was a gift. Just make the most of it." The Doctor's smile was bittersweet. He produced a small, blue book from his jacket pocket. River's diary. He gave it to Donna. "I think she would want you to have this."

He held out his hand, which she took without hesitation. "Leadworth, then on to Felspoon."

* * *

><p>END<p> 


End file.
